Wash the raisins carefully.
Cook in the boiling water until plump.
Add flour and sugar, mixed; cook a few minutes until mixture thickens.
Cool.
Add lemon juice, rind, and chopped walnuts.
Pour in a pie tin, lined with pastry.
Cover with pastry.
Bake in a hot oven (450°F) 35 or 40 minutes.
Reduce the heat to 350° F during last 10 minutes.